First molecular detection of canine herpesvirus 1 (CaHV-1) in the Eastern Brazilian Amazon.

BACKGROUND: Canine herpesvirus type 1 (CaHV-1) infects dogs and is associated with neonatal deaths and reproductive, ocular, neurological, and respiratory problems. In Brazil, reports of CaHV-1 have been restricted to the southeast and south regions, particularly in municipalities in the state of Rio Grande do Sul. OBJECTIVES: To assess the presence and variability of CaHV-1 in canine populations in the state of Pará, North Brazil. METHODS: Biological samples from 159 dogs from 4 municipalities in the State of Pará were evaluated using polymerase chain reaction and phylogenetic analyses, with the target being the viral enzyme, thymidine kinase. RESULTS: CaHV-1 was detected in 13 dogs (8.2%), with 2 animals being from the municipality of Santa Bárbara do Pará, 8 from Algodoal Island, 2 from Salinópolis, and one from Capanema. The study sequences revealed 100% identity among themselves and 64% to 100% identity with the other nucleotide sequences from Australia, Brazil, United Kingdom, and United States, including 100% identity with the 2002 isolate from Australia. The 1996 isolate from France was grouped in a branch that was different from the sequence of this study. CONCLUSIONS: This study presents the first molecular detection of CaHV-1 in dogs from the Amazon region in northern Brazil. The nucleotide identity between the strains and cytosine insertion in the sequences isolated in this study suggests at least 2 strains of CaHV-1 circulating in Brazil (Pará and BTU-1).

Achados clínicos e patológicos em cães infectados naturalmente por herpesvírus canino / Clinical and pathological Findings in dogs infected naturally by canine herpes virus

Descrevem-se os achados clínicos e patológicos e os exames laboratoriais de filhotes de cães com diagnóstico post mortem de infecção por herpesvírus canino. Os casos ocorreram em duas propriedades da Cidade de Porto Alegre, Rio Grande do Sul, em abril de 2007 e julho de 2008. Clinicamente, os cães apresentaram anorexia, apatia, choro e dispneia. A morte dos cães ocorreu após 24-72 horas do início dos sinais clínicos. Na necropsia observaram-se hemorragia multifocal renal e hepatomegalia com petéquias e pontos brancos na superfície natural do fígado. Os pulmões se apresentaram não-colapsados e vermelhos. Havia esplenomegalia e, em alguns cães, petéquias na superfície capsular do baço. Aumento dos linfonodos mesentéricos e do timo foi observado. Lesões microscópicas incluíram hemorragia e necrose multifocal em células epiteliais tubulares renais, hepatócitos e tecidos linfoides. Nos pulmões, havia necrose alveolar multifocal acentuada com abundante material fibrinoso e infiltrado inflamatório misto de intensidade variada. Ocasionais corpúsculos de inclusão intranucleares em áreas periféricas à necrose foram identificados em hepatócitos, células epiteliais de túbulos renais e células alveolares. Amostras de fígado, rim e pulmão foram positivas na imunofluorescência direta para herpesvírus canino tipo 1 (CHV-1). O diagnóstico de infecção por herpesvírus foi baseado nos achados de necropsia, histológicos e de imunofluorescência positiva em tecidos usando anticorpo anti-CHV-1. De nosso conhecimento, este é o primeiro relato da identificação do CHV-1 no Brasil, embora achados clínico-patológicos anteriores já sugerissem a presença do agente na população canina do país.

The clinic and pathological findings and laboratorial testing of puppies with postmortem diagnosis of canine herpesvirus infection are described. The cases occurred in two households of Porto Alegre, RS, in April 2007 and July 2008. The puppies presented anorexia, depression, cry and dyspnea, followed by death about 24-72 hours after the onset of clinical signs. At necropsy multifocal pin point hemorrhages were observed in the kidneys. The liver was enlarged with petechiae and white foci on the surface. The lungs were red and did not collapse. The spleen was enlarged and, in some cases, with petechiae on the capsular surface. Mesenteric lymph nodes and thymus were enlarged. Microscopic lesions included hemorrhages and multifocal necrosis of the renal tubular epithelial cells, hepatocytes and lymphoid tissues. In the lungs there was severe multifocal alveolar necrosis with abundant fibrin deposits and a mixed inflammatory infiltrate of variable intensity. Intranuclear inclusion bodies were identified in the periphery of necrotic areas in hepatocytes, renal tubular epithelial cells and alveolar cells. Samples of liver, kidney and lung were positive in the direct immunofluorescence test for canine herpes virus type 1 (CHV-1). The diagnosis was based on epidemiological data, necropsy findings, histological lesions and positive immunofluorescence results using CHV-1 antibody in tissue samples. To our knowledge, this is the first report of the identification of CHV-1 in Brazil, although previous clinic and pathological findings already suggested the presence of the virus in Brazilian canine population.